Digital portfolios can serve as evidence that students have met curriculum standards and allow for formative and summative assessment. When deciding content, teachers should select students' work that best illustrates their knowledge and is aligned to standards. Portfolios have progressed from paper to digital formats classified by Helen Barrett, ranging from early elementary programs like KidPix to Inspiration-based and PowerPoint versions to modern web-based portfolios using applications like PageFlakes that do not require HTML skills. Additional online tools like Box.net and SlideShare can also be used for digital portfolio content and sharing.